Comment 1 for bug 1256345

In order to allow the same topic name to be used for different contexts, a unique 'name' would also need need to be passed into the TopicConsumers for impl_rabbit and impl_qpid (e.g. prepending the exchange to the topic), since without that the topic name will be used for the queue name which would cause messages for the different contexts to be interleaved on the same queue. (Or so I believe! I'm still getting familiar with the code!).